It's the difference between cheap and expensive, not tv versus monitor. The cheap 4k TVs and monitors do 30. The $3000+ ones like the Sonys do 120hz. It will change quickly, though it looks like < 1000 means TN screens.

I disagree, a monitor is 60 Hz, a TV typically 30Hz, yes, a few TV's are talking about 60Hz input, but not many, and it's mostly just talk of upgrades for now, with one exception I'm aware of. However, you'll not find monitors below 60Hz.

If you really think there's a 30Hz monitor, please provide a link I would like to research it, and there's no way you'll find a TV with a 120Hz input at UHD resolution as there's no consumer signal cable capable of 120Hz UHD, short of running dual channel Thunderbolt and no one is doing that yet. Any claim of 120Hz UHD is doing frame rate sub-sampling/scaling within the device, nothing takes a 120Hz input at UHD resolution.

People are buying the Seikos for "monitor" use. For $499, it tempts.

The next step up are the double headed monitors - even the expensive Asus 31" is two 1920x2160 displays.

And then you have the pricy TVs, all of which are outputting at 120hz. No, the source over HDMI wouldn't be 120...LEDs have been displaying faster than input for a long time. My plasma claims to be 600hz.